Automatic central buffer couplings for rail vehicles

ABSTRACT

An automatic central buffer coupling has an arm connected to a pivot member for connection to a rail vehicle, and pulling and buffing jaws, with male and female guide assemblies to guide couplings relative to each other for coupling. The coupling is made up in a fabricated structure by component parts secured together by welding. The arm is in a box structure including a master member which extends in one piece from the pivot member to the buffing jaw member, for receiving coupling forces.

United States Patent Dailly et al.

AUTOMATIC CENTRAL BUFFER COUPLINGS FOR RAIL VEHICLES Inventors: Georges Paul Dailly, 5, rue G.

Bostarron; Raymond Marcel Lefebvre, 7, rue G. Bostsarron, both of 59590 Raismes (Nord), France Filed: Dec. 13, 1973 Appl. No.: 424,452

Foreign Application Priority Data Dec. 13, 1972 France 72.44288 Dec. 4, 1973 France 73.43130 U.S. Cl 213/100 W Int. Cl. B61g 3/10 Field of Search 213/100 R, 100 W References Cited UNITED STATES PATENTS 10/1916 Willison 213/100 W [451 Mar. 18, 1975 2,963,174 12/1960 Metzger 7. 213/100 W FOREIGN PATENTS OR APPLICATIONS 1,193,531 5/1965 Germany 213/100 W Primary ExaminerM. Henson Wood, Jr. Assistant E.raminerGene A. Church Attorney, Agent, or FirmDil1er, Brown, Ramik & Wight [57] ABSTRACT An automatic central buffer coupling has an arm connected to a pivot member for connection to a rail vehicle, and pulling and buffing jaws, with male and female guide assemblies to guide couplings relative to each other for coupling. The coupling is made up in a fabricated structure by component parts secured to gether by welding. The arm is in a box structure including a'master member which extends in one piece from the pivot member to the buffing jaw member, for receiving coupling forces.

35 Claims, 7 Drawing Figures PATENTEBHAR 1 8 I975 3,871 ,531

snmuura AUTOMATIC CENTRAL BUFFER COUPLINGS FOR RAIL VEHICLES BACKGROUND OF THE INVENTION Automatic central buffer couplings of the Willison type are known in various forms, and are generally produced by foundry casting the coupling body which essentially comprises an arm carrying pulling and buffing jaws, and male and female guide assemblies for bringing two couplings together for coupling engagement. Buffing and pulling stresses in the coupling require the components to be perfectly uniform in structure, and they have to be subjected to mechanical checks of extreme stringency. In the particular case of coupling heads, because of the presence of portions of widely differing masses, the inherent difficulties of foundry casting, for example inclusions, blow holes and geometric inaccuracies, are particularly apparent. In addition, because of the extremely severe working conditions of rail couplings, and the severe tests which are laid down in construction specifications relating to such couplings, even a very minor casting defect can result in a member which is virtually completed, being rejected as not up to standard.

In addition, the specifications drawn up by the organisations which use railway couplings include particular clauses which cover on the one hand exceptional forces on such couplings and on the other hand, the cooperation between automatic systems for coupling railway carriages together, and for coupling the various conduits on such carriages. For example the pivot head which co-operates with the central buffer must have a stabilising action, which is operative to counteract derailment of the carriages. Also, the mechanism for actuating the couplers which is essentially housed at the level of the male and female guide means, below the buffing and pulling jaws, requires the surrounding elements of the coupling to be of suitable structure.

SUMMARY OF THE INVENTION It is an object of the invention toprovide an automatic central buffer coupling which does not suffer from the above disadvantages of couplings which are produced by casting, with the inherent danger of the whole coupling casting being liable to rejection, due to a relatively minor casting defect in a comparatively unimportant part of the casting.

A further object of the invention is a coupling of fabricated construction with a main member for carrying the principal operating stresses on the coupling.

Yet another object of the invention is to provide a coupling which permits its component parts to be checked for quality of manufacture as the parts are themselves manufactured, so that any defective parts are discovered before final assembly of the coupling unit, and the final assembly can be done with a high degree of precision Still another object is a rail vehicle coupling which is adapted to the optimum extent to the dynamic stresses imposed on it in operation and also able to withstand exceptional overstressing, by means of specific component parts of the coupling being specifically designed and dimensioned with these factors in mind. also resulting in lighter weight for the same strength.

It is yet a further object to produce a coupling which does not require the casting of complex shapes for forming housings for the operating mechanisms of the coupling.

In accordance with the invention, the'coupling has a coupling arm with a pivot member at one end, for connection to a rail vehicle, and with a buffing jaw and a pulling jaw at the other forward end. Also at the forward end is a male guide assembly and a female guide assembly, the male and female guide assemblies of two couplings to be coupled, co-operating to bring the couplings towards the correct relative positions for the actual coupling operation. Between the two jaws is a frontal plate surface, with an aperture for housing latching apparatus, while below the frontal plate is a passageway for conduits. The coupling is formed by a welded assembly of a plurality of component parts constructed around a main or master member which extends continuously from the pivot member to the buffing jaw.

The master member can be a buffing plate carrying at its forward end a buffing jaw member of generally U-shaped cross-section. Making the buffing plate the said master member meets the requirement for causing the forces applied to the coupling to be carried by a suitably shaped and dimensioned manner. The buffing plate can be completed, to form the coupling arm, by upper and lower plates and an additional side plate or body portion, forming a box structure. Such a box structure affords, with minimum weight, the best mechanical properties as regards resistance to alternate pulling and buffing forces. The box structure can be of rectangular cross-section and receive a projecting lug or core on the pivot member for securing the pivot member to the coupling arm.

Depending on their configuration, which affords the possibility of reducing the weight of the coupling, and possible fatique thereof, the components of the coupling can be produced either from cut and fashioned metal plate, or by die-shaping such as die-stamping, die-forging such as drop-forging, or die-casting. Obviously the metal plate qualities and the strengths of the steel can be selected in a particularly rational manner.

The male guide assembly which is disposed in vertical alignment with the pulling jaw comprise a die-shaped horn member and an inclined surface member of metal plate rearwardly thereof, which are assembled around a lower extension of the buffing jaw member, a dieshaped member forming part of the side wall of the passageway also being connected by its upper edge to said inclined surface member.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a general perspective view of the coupling,

FIG. 2 is an exploded view of the coupling showing the component parts thereof,

FIG. 3 is a side view of the forward end of the coupling, as seen from the right-hand side in FIG. 1,

FIG. 4 is a side view of the forward end of the coupling, as seen from the side opposite that of FIG. 3,

FIG. 5 is a front elevational view of the coupling,

FIG. 6 is a perspective view from above of a part of the forward end of the coupling arm,

FIG. 7 is a view, from the front, of the underside of the coupling, the coupling being shown in an inverted position for ease of viewing in the figure.

DESCRIPTION OF THE PREFERRED EMBODIMENT In order to keep the description succinct, the following description will not include in detail all the components used in the coupling, insofar as the nature and the function thereof are known to the man skilled in the art and are part of known mechanisms which can be simply integrated into and fitted onto the coupling.

The coupling comprises an arm 1 which carries at its rearward end a pivot member 2 and at its front end a jaw assembly 3. Below the jaw assembly 3 are disposed a male guide assembly 4 and a female guide assembly 5. The two guide assemblies 4 and 5 are separated by a passageway 6 for conduits, a bottom member 7 extending below the guide assemblies 4 and 5 and forming the lower wall of the passageway 6.

The jaw assembly 3 comprises a small or buffing jaw 31 and a large or pulling jaw 32, which are connected by a frontal plate 33. The male guide assembly 4 which is located at the bottom of the buffing jaw 31 comprises a guide horn 41 which is extended rearwardly by a member 42 providing an inclined guide surface. The female guide assembly 5 which is vertically below the pulling jaw 32 is defined by a restraining guide jaw 51, a vertical deflector 52 and a shoe 53.

The bottom member 7 is formed by a metal base plate 71 (see FIG. 2) and a shoe-carrier block 73, the connection of which in line with the passageway 6 can also be seen in FIG. 7. The base plate 71 carries the male guide assembly 4, as will be described in detail later, and forms the lower surface delimiting the passageway 6. The sides of the passageway 6 are formed by two wall members 61 and 62 (see FIGS. 2, 4 and 7).

For the sake of convenience of description hereinafter. where appropriate, the wall member 61 carrying the buffing jaw 31 will be designated the left-hand side of the coupling, and that 62 carrying the pulling jaw 32 will be designated the right-hand side.

The arm 1 is a box structure formed by assembling two side members, namely a buffing plate 11 and a side plate or body portion 12, with two horizontal plates, namely an upper plate 13 and a lower plate 14. The buffing plate 11 is the main or master member around which all the other components of the coupling are assembled by welding in a structural grouping, to form a fabricated coupling. At the end towards the pivot member 2, the arm 1 is a tube of substantially rectangular cross-section,, with its long sides horizontal. As shown in FIG. 2, the pivot member 2 comprises a body 21 with an aperture 22 for receiving a coupling assembly pivot (not shown), while the body 21 is extended in the direction of the arm by a projecting anchoring lug or core 23. The lug 23 is hollowed out in its axis, for housing a pivot spring, although this is not visible in the drawings. At its end part towards the arm 1, the lug carries a blind or closed-end portion 24 forming an abutment for the end of the pivot spring remote from the assembly pivot. It will be noted (see FIG. 2) that, in its upper surface, the body 21 of the pivot member 2 has a recessed portion forming a substantially semicircular shoulder 25 which can be produced by die-shaping. A similar shoulder is provided on the lower face of the body 21. In their turn, rearward terminal portions 132 and 142 of the plates 13 and 14 are of semi-circular shape, to match the shape of the shoulders 25 on the body 21. In this way extended weld joints can be made between the body 21 and the plates 13 and 14, to strengthen the connection between these components. Between the pivot member 2 and the jaw assembly the arm 1 has a tubular shank portion which is stiffened in the region of its engagement with the body 21 by means of an arm-strengthening metal plate 15. The plate 15 is mounted within the arm 1 equidistantly from the plates 13 and 14 and parallel thereto, being welded between the plate 11 and the plate portion 12, so that when the arm 1 is joined to the pivot member 2 the plate 15 abuts against the end portion 24 and acts as a cross-bracing member.

The buffing plate 11 is in one piece and extends from the pivot member 2 to the buffing jaw 31, as will be seen from the above; the buffing plate 11 comprises a shank portion 111 and a front plate portion 112, with an outwardly inclined plate portion 113 being disposed between and connecting the shank portion 111 and the plate 112. The angle of connection between the shank portion 111 and the inclined plate portion 113 is smaller than the angle of connection between the plate portion 113 and the front plate portion 112 such that the relative angle between the shank portion 111 and the front plate portion 113 is an acute angle in the region for example of 15.

The side plate portion 12 is in the form of a flat strip with a shank portion 121 and a front portion 122 which in its lower part has a cut-out for receiving an unlatching actuating guide 80. While the edges ofthe side plate portion 12 are substantially parallel to each other in the shank portion 121, the upper edge diverges slightly from the lower edge, starting from a central zone, towards the front of the portion 12, in order to be adapted to the shape (shown in FIG. 2) of the upper plate 13. The plates 13 and 14 have flat shank portions 131 and 141 which are substantially identical, with parallel edges, and enlarged front portions, the enlarged front portion 133 of the upper plate 13 rising slightly.

The edges of the plates 13 and 14 at the left-hand side in FIG. 2 are adapted to the lateral shape of the buffing plate 11, from the shank portion 111 into the vicinity of the forward terminal edge of the front plate portion 112; in this region, these edges are shaped so as to be assembled to an upper part 331 (FIG. 6) of the frontal plate 33 and the pulling jaw 32. FIGS. 2 and 6 show in part the details of this assembly at the top level of the plate 13; the frontal plate 33 has a body portion 331 which bears by way of a part of its rearward face into the cut-out provided towards the front end of the plate 13, while the pulling jaw 32 is connected by its rearward vertical edge to the lateral edge of the front face of the plate 33.

The edges of the plates 13 and 14 at the right-hand side in FIG. 2 are enlarged and extended forwardly, to form stiffening web portions to embrace the body portion 331 of the frontal plate 33 and the pulling jaw 32, the terminal edge of which forms a common projection or nose 324 (FIG. 4) which is delimited in a vertical direction by the forward end points of the plates 13 and 14. Also connected to the nose 324 is the front part of an intermediate strengthening plate 85 which is disposed between and at equal distances from the plates 13 and 14 and parallel to the lower plate 14. The plate 85 bears across the guide and strengthens the arm 1 at the level of the pulling jaw 32.

The frontal plate 33 comprises the upper part 331 and a solid bottom part 332 (see FIGS. 2 and 7). By means of its body part 331, the frontal plate 33 therefore forms a top cross-bracing member across the open box structure of the arm 1, as formed by the two main plates 13 and 14, the strengthening plate and the side plate portion 12 on the one hand, and the buffing plate 11 on the other hand. The plate 33 has an opening which is set off-centre towards the buffing jaw 31, intended for the passage of the latching members.

As can be seen from FIGS. 1 to 3 and 6, the inclined plate portion 113 and the front plate portion 112 of the buffing plate 11 have an upper edge which is raised above the plane of the plate 13 and which is connected to the level of the plane of the plate 13 by a curved edge 114. The strip portion above the plane of the plate 13 forms, in conjunction with the adjacent region of the plate 13, a right-angle corner shape on which is fitted a cap 81 of suitable shape to form a housing 82 for protecting a known latching mechanism (not shown). The housing 82 is provided with a hook member 83 forming a gripping means for a lifting hook, and has an end opening for an abutment plate 92.

The buffing jaw 31 which is formed by a member whose cross-section is of U-shape whose limb portions 313 and 314 (FIG. 6) are of unequal lengths (see also FIG. 2) has an upper part 311 joined to the forward ter minal edge of the buffing plate 11, and is extended by a bottom portion 312. In the upper part 311 the U- shape is maintained intact, whereas the bottom portion 312 comprises only the base portion of the U-shape, and a limb portion 317 of reduced length. The forward limb portion 313 (FIG. 6) of the U-shaped member is longer than the rearward limb portion 314, by approximately the thickness of the buffing plate 11, so that when the limb portion 314 isapplied against the outward face of the plate 11, the forward limb portion 313 forms a support abutment against which the vertical edge of the plate 11 bears and to which it is joined.

Slightly inwardly from the upper and lower ends of the upper part 311, the buffing jaw 31 is strengthened by an assembly of upper and lower plates 315 respectively (FIGS. 1 and 2) which are of a cross-sectional shape adapted to the internal cross-sectional shape of the buffing jaw 31, with corners removed from the plates 315 to provide a passage for a flow of water through the buffing jaw 31. The plates 315 impart to the jaw the necessary degree of mechanical strength, allied with economic utilisation of material.

The bottom portion 312 of the pulling jaw 31 is of substantially right-angle cross-section of which the limb portion which is in line with the base of the U-shape of the upper part 311 of the jaw member is connected to the inclined guide surface member 42 and to born 41 of the male guide assembly 4 while the other, front, limb portion 317 of the right-angle cross-section, which is located in the plane of the buffing face of the jaw 31 comprises at its base in the vicinity of the inclined guide surface member 42 a portion 316 of increased transverse thickness, intended for stiffening the jaw member.

Referring now to FIGS. 2 and 6, the pulling jaw 32 comprises a shaped member having three substantially vertical. faces 321, 322 and 323 (FIG. 6) which are angularly displaced relative to each other. The rearward face 321 is joined by way of its rearward vertical edge to the lateral edge of the front face of the body portion 331 of the front plate 33, while the forward face 323 forms the above-mentioned nose 324. The faces 321 and 323 are connected by an intermediate face 322, the three faces being so angled relative to each other that the jaw 32 has the general cross-sectional shape of a Z. The upper edge of the jaw 32 starts from the highest point of the body. portion 331 of the frontal plate 33, and slopes progressively down to the level of the plate 13 in line with the nose 324.

In their lower part, the three faces 321, 322 and 323 of the pulling jaw 32 merge below the level of the plate 14, forming a wedge-shaped connection to the front nose edge of the horn 51 of the female guide assembly 5.

As stated above, the female guide assembly 5 also comprises the vertical deflector 52 and the shoe 53. The horn 51 is in the general shape of a triangle of which one of the sides or edges is joined to the lower part of the pullingjaw 32, another side or edge is joined to the side face of the deflector 52, while the third side or edge extends outwardly from the bottom of the front edge of the pulling jaw 32 to a projection or pointed portion 523 of the deflector 52. As can be seen from FIG. 2, the deflector 52 has a cut-out in its side at its lower end, the cut-out defining a base portion 522 and a wing portion 521 whose end forms the projection 523 which is the point of connection between the deflector 52 and the third edge or side of the horn 51. The upper edge of the deflector 52 is joined to the lower face of the plate 14. In line with the base portion 522 and in front thereof (see FIGS. 1 and 5) in the shoe 53 of which is of known external configuration. The shoe 53 is made by die-shaping, with a shoe carrier 73 which will be described in detail hereinafter and which is joined by its upper face to the bottom edge of the base portion 522 of the deflector 52, and to the bottom edge of the base portion 332 of the frontal plate 33.

FIGS. 3 and 5 show the guide passage which is defined in a vertical direction by the lower face of the horn 51 and the shoe 53, and at one side by the deflector 52.

The male guide assembly 4 is positioned at the buff ing jaw side of the coupling. The horn 41 of known external configuration is joined by its base to the base plate 71 and by its inward face to the base portion 312 of the buffing jaw 31. The inclined guide surface member 42 is so arranged as to form a rearward and upwardly inclined extension of the upper face of the born 41, the general shape of the inclined guide surface of the member 42 being triangular. As stated above, the forward side or edge of the inclined guide surface mem ber 42 is joined to the rear of the horn 41, another side or edge to the lower edge, which is of associated shape, of the front plate portion 112 forming part of the buffing plate 11, while the third side or edge of the member 42 extends from the horn 41 to the rearward lower end of the plate portion 112.

FIG. 4 shows the male guide assembly, which is intended to co-operate with a female guide assembly 5 of a co-acting coupling for guided coupling.

The passageway 6, as defined by two vertical side walls 61 and 62 (FIGS. 2, 3 and 5) and the corresponding region of the base plate 71, is partially closed in its upper part by the lower end face of the body portion 331 of the frontal plate 33, and that ofa rearward plate 84. a

For reasons of a kinematic nature, the general axis 0 the passageway 6 is angularly displaced through about 30 with respect to the longitudinal centre line of the shank portion of the arm 1. As viewed at the front of the coupling, the axis of the passageway 6 is displaced towards the buffing jaw side or left-hand side of the coupling. The wall 61 is positioned vertically below the.

edge of the limb portion 314 (FIG. 6) of the top part of the buffing jaw 31 and is joined at that level, by means of its upper edge face, to the lower face of the inclined guide surface member 42. The forward terminal edge of the wall 61 is set slightly back relative to the base portion 312 of the buffing jaw member, while the base part of the wall 61 is secured to the base plate 71. A rear opening in the wall member 61 defines upper and lower arm portions which are each extended by a horizontal bearing member for carrying a fixing shaft for the couplers.

The wall 62 is formed by a die-shaped post member 621 which at its lower part carries a horizontal bearing member 622 for the coupler fixing shaft, and three plate members 623, 624 and 625 which are assembled, in vertical alignment, with the post member 621, to form an apertured wall (see also FIG. 7). The forward terminal edge of the wall 62 is common with the base portion 332 of the frontal plate 33, and its base is fixed to the base plate 71, while its upper end face is joined locally to the lower plate 14 and to the plate 84. Thus defined, this wall has openings adapted to the known system for actuating the couplers.

FIG. 7 shows a view on to the lower face of the base plate 71 and the shoe carrier member 73, and illustrates its three main plates: plate portion 74 which is associated with a seating for the horn 41, plate portion 72 which is in the same plane as the plate portion 74 but displaced rearwardly thereof. the plate portion 72 forming part of the bottom 7 of the passage-way 6, and the plate 75 which forms the apertured base of the carrier member 73.

The shoe carrier member 73 has an upper face (seen for example as in FIG. 1) which is raised with respect to that of the base plate 72. The shoe 53 shown is an integral part of and projects from the shoe carrier member which is also so shaped as to form a shaped seat for the base portion 332 of the frontal plate 33.

The bottom 7 formed by the assembly of the base plate 71, 72 and the shoe carrier member 73 therefore serves as a base on the one hand for the base portion 332 of the smalljaw, the horn 41, the side walls 61 and 62, the frontal plate 33 and the deflector 52, and also forms a cross-bracing member between the side walls of the passageway 6.

FIG. 2 also shows rib members 43 and 44 to strengthen the guide assembly 4, one rib member 43 (see also FIG. 4) being disposed below the inclined guide surface member 42 and in abutment against the rearward face of the horn 41, while the other rib member 44 (see also FIG. 4) is disposed on the edge of the upper face of the base plate 71, and is also in abutment against the rearward face of the horn 41.

As stated above, some components of the coupling shown in the drawings, in particular FIG. 2, are not illustrated and described above, such components being parts of mechanisms whose configuration and operation are known to the man skilled in the art. Thus, below the lower face of the guide 80 (which is formed by two half-shell members), there can be seen an extension which forms an upper bearing member 87 which is coaxial with a lower bearing member 86 which is produced by die-shaping and which is attached to the upper face of the shoe carrier member 73. A part 89 forms a die-shaped carrier for a co-acting latch and suspension means, while reference 90 denotes a shaft support ring and 91 shows a latch support shaft.

It will be apparent from the foregoing description that the components of the above coupling are made as appropriate from out and shaped metal plate or are parts produced by die-shaping which can include diestamping, die-forging such as drop-forging, or pressure die-casting, as may be suitable.

The operating principle of such a coupling is known and will therefore not be described herein.

It will be apparent that, with the technological requirements made on railway couplings, in mind, the coupling assembled by the assembly method described above, offers inter alia the following advantages:

as regards mechanical strength, the assembly method makes it possible to adapt the coupling components to both normal and exceptional dynamic stresses, and to cause such stresses to be absorbed selectively by elements which are dimensioned for that purpose, by means of a very carefully elaborated structure;

as regards consumption of material, in such an assembly, which is rationally adapted to the conditions set out in a railway coupling specification, each member can radily be of the optimum weight, and, for equal strength, the coupling will be lower in weight than a coupling produced by foundry casting;

as regards housing of the coupling operating mechanisms, it is easily possible to provide spaces and housings for the parts of the mechanisms, without having recourse to highly complex and particularly difficult casting moulds, such housings being defined by the cooperation and corelation of the relevant component parts.

Finally, as regards series production, this method of assembly affords the possibility of providing parts which can be assembled with precision and which can be checked at the various stages of assembly, while the man skilled in the art will appreciate that, by virtue of the constructional features of the coupling the construction of the above coupling makes it possible easily to adapt rates of manufacturing, with a low level of investment.

Besides the advantages already set out above, relating to adapting the members to their respective functions, the possiblity of rationally selecting the prime materials for manufacturing and the manufacturing process, the possibility of optimising the weight of each component, progressive checking in the course of assembly, and accuracy in the dimensions of the members, all these advantages contributingto viability of the finished product and a reduction in cost price, it should also be noted that the coupling also affords the possibility of periodic checking of its condition by a simple direct visual examination, linked with convenient maintainance and, in the event of an accident, repair on the spot by welding.

The above coupling is described only by way of example of this invention, and various modifications can be made without thereby departing from the spirit and the scope of the invention.

We claim:

1. In an automatic central buffer coupling including a coupling arm having a forward end and a rearward end, a buffing jaw and a pulling jaw at the forward end of the arm, a pivot member at the rearward end of the arm, a frontal plate between the buffing and pulling jaws, the frontal plate defining an aperture, latching means in the aperture in the frontal plate, two side walls delimiting below the frontal plate a conduit passageway, and a bottom member closing the bottom of the passageway, the improvement that comprises the assembly by welding of the coupling components about a master member which extends continuously from the buffing jaw to the pivot member.

2. A coupling according to claim 1 wherein the master member is a buffing plate providing a forward end part'on which is carried a buffing jaw-forming member formed by a shaped member of generally U-shaped cross-section.

3. A coupling according to claim 2 wherein in the region in which the buffing jaw member co-operates with said buffing plate, the U-shaped cross-section of the buffing jaw member has limb portions of unequal lengths, the longer thereof extending adjacent the forward vertical terminal edge of the buffing plate.

4. A coupling according to claim 2 wherein the coupling arm is formed by the assembly of the buffing plate in a box structure with three plate members forming respectively an upper plate, a lower plate, and a side plate portion which extends parallel to at least a part of the buffing plate.

5. A coupling according to claim 4 wherein an unlatching actuating means guide is supported on the lower plate.

6. A coupling according to claim 4 wherein said box structure forms at the rearward end of the arm a tube part of substantially rectangular cross-section whose long edges extend horizontally, and said pivot member comprises a body portion carrying an axial extension forming an anchoring lug portion of a cross-section adapted to engage within said tube part.

7. A coupling according to claim 6 wherein said anchoring lug portion is hollowed axially and is axially extended forwardly by a blind-end member which is disposed within said tube part, the hollow in the anchoring lug portion and the blind-end member forming a housing receiving a pivot spring having a forward end which abuts against the blind end of said member.

8. A coupling according to claim 7 wherein the rearward end of each of said'upper and lower plates is disposed rearwardly of said anchoring lug portion and is of a substantially semi-circular convex terminal profile,

and wherein the pivot member body portion has on upper and lower surfaces shoulders of substantially semi-circular profile so arranged that the convex terminal profile of each of the upper and lower plates fits to the respective shoulder.

9. A coupling according to claim 7 wherein adjacent the rearward end of the box structure there is provided a shaped reinforcing metal plate member which extends parallel to the upper and lower plates and is equidistant therefrom and whose rearward end abuts against and is fastened to the blind-end face of the blind-end member the plate member also being secured as a cross-bracing means to the buffing plate and the side plate portion.

10. A coupling according to claim 4 wherein said upper and lower plates are enlarged forwardly into stiffening wing portions and wherein a pulling jawforming member is secured to said wing portions.

11. A coupling according to claim 10 wherein an intermediate strengthening plate is disposed between said upper and lower plates parallel to the lower plate and is secured along one of its longitudinal edges to said side plate portion, its forward end portion being so shaped as also to be joined to said pulling jaw-forming member.

12. A coupling according to claim ll'wherein an unlatching actuating means guide is secured between the lower and the intermediate plates;

13. A coupling according to claim 10 wherein the frontal plate has an upper part which is disposed as a cross-bracing means between the part of the buffing plate carrying the buffing jaw member and the rearward edge of the pulling jaw member.

14. A coupling according to claim 13 wherein said side plate portion has a front edge which abuts against said upper part of the frontal plate, in the vicinity of the rearward edge of the pulling jaw member.

15. A coupling according to claim 4 wherein said buffing plate has, in a forward direction, a shank plate portion parallel to the side plate portion, an intermediate plate portion which is turned outwardly through a given angle, and a front plate portion which is diverted inwardly through an angle greater than said given angle, so as to be at an acute angle to the shank plate portion.

16. A coupling according to claim 15 wherein said intermediate and front plate portions project upwardly above said upper plate and a cap metal plate member is secured to the upwardly projecting parts rearwardly of the frontal plate, thereby to form a housing for latching mechanism.

17. A coupling according to claim 3 wherein a plurality of stiffening plate members are fitted within the buffing jaw member, the shape of the plate members being substantially adapted to the cross-sectional shape of the buffing jaw member, except for angle corners of the cross-section of the buffing jaw member, at which corners openings are provided for liquid flow through the buffing jaw member.

18. A coupling according to claim 1 and further including a male guide assembly arranged in vertical alignment with the buffing jaw.

19. A coupling according to claim 18 wherein said male guide assembly comprises a forwardly extending horn member and an inclined guide surface member of metal plate extending rearwardly of the horn member, the horn member and the guide surface member being assembled around a lower portion of the buffing jaw member and a member which forms part of the adjacent said side wall of the passageway also being connected at its upper edge to said guide surface member.

20. A coupling according to claim 19 wherein said lower portion of the buffing jaw member is of a crosssection comprising two limb portions at right angles to each other, one limb portion being secured to the horn.

member and the guide surface member and the other limb portion comprising, at the level at which the lower portion is secured to the horn member, a portion which is shaped in transverse section and which is increased in thickness for stiffening purposes.

21. A coupling according to claim 19 wherein said inclined guide surface member is strengthened by a rib portion of triangular shape, one of its edges being secured to the inclined guide surface member, a second of its edges being secured to the horn member, and the third of its edges extending outwardly.

22. A coupling according to claim 19 wherein the bottom member of the passageway is formed by a metal base plate member which extends below said horn member of the male guide assembly with which it is made peripherally integral.

23. A coupling according to claim 1 wherein the one of said side walls that is at the pulling jaw side of the coupling includes a post member which in its lower part carries a horizontal bearing for a coupler fixing shaft, and three metal plate members, respectively an upper, a middle and a lower plate member, the plate members being joined at one of their side edges to the post member in a single vertical plane, thereby to form an apertured wall portion.

24. A coupling according to claim 1 and further including a female guide assembly disposed in vertical alignment with the pulling jaw.

25. A coupling according to claim 24 wherein said female guide assembly comprises a laterally projecting restraining horn member, a vertical deflector below the horn member, and a projecting portion forming a shoe below the deflector member, the horn member, deflector and shoe defining a guide passage for receiving a male guide assembly of a co-acting coupling for assisting in coupling.

26. A coupling according to claim 25 wherein said frontal plate has a substantially vertical solid base portion having a bottom end which is secured to an adjacent part of a member carrying said shoe, the base portion also being secured to said horn member, and over the whole of its adjacent vertical edge to the deflector.

27. A coupling according to claim 26 wherein said shoe carrier member co-operates by way of its upper face with the deflector and a post member forming part of the passageway side wall at the pulling jaw side of the coupling.

28. A coupling according to claim 26 wherein a member forming a lower bearing for an advance spindle is secured on the upper face of the shoe carrier member, rearwardly of said deflector and in vertical alignment with an upper bearing member which is associated with an unlatching actuating guide means.

29. A coupling according to claim 26 wherein said shoe is formed by a shaped projecting extension on the upper face of the shoe carrier member.

30. A coupling according to claim 26 wherein said bottom member is formed by a metal base plate member and the shoe-carrier member which is joined to the base plate member.

31. An automatic central buffer coupling of the Willison type, comprising a coupling arm providing a forward end and a rearward end, a buffing jaw at the forward end of the coupling arm, a pulling jaw at the forward end of the coupling arm adjacent the buffing jaw, a first guide assembly adjacent the buffing jaw, a second guide assembly adjacent the pulling jaw, the guide assemblies of two said couplings to be coupled being co-operable for mutual relative positioning thereof, a pivot member at the rearward end of the arm, and a main stress-carrying member which extends in one continuous piece from the pivot member to the buffing jaw, the components thus forming the coupling being assembled together by welding around said main member as the basic component of the coupling.

32. A coupling according to claim 31 wherein the arm is of a box structure and the main member is a buffing plate which forms a side of the box structure, the buffing jaw being formed by a buffing jaw member welded to the forward end of the buffer plate.

33. A coupling according to claim 31 wherein a frontal plate is disposed between the bufflng and pulling jaws and defines an aperture for a latching mechanism.

34. A coupling according to claim 31 wherein the coupling arm includes two side wall members and a base member which define a passageway for conduit means for interconnecting two coupled rail vehicles.

35. A coupling according to claim 31 wherein said first guide assembly comprises a forwardly projecting guide horn which is extended rearwardly by an inclined surface, and the second guide assembly forms a passage for receiving the guide horn of a co-acting coupling to be coupled, the passage being formed by a laterally projecting restraining born, a vertical deflector surface member below the restraining horn, and a substantially laterally and forwardly projecting shoe disposed below 

1. In an automatic central buffer coupling including a coupling arm having a forward end and a rearward end, a buffing jaw and a pulling jaw at the forward end of the arm, a pivot member at the rearward end of the arm, a frontal plate between the buffing and pulling jaws, the frontal plate defining an aperture, latching means in the aperture in the frontal plate, two side walls delimiting below the frontal plate a conduit passageway, and a bottom member closing the bottom of the passageway, the improvement that comprises the assembly by welding of the coupling components about a master member which extends continuously from the buffing jaw to the pivot member.
 2. A coupling according to claim 1 wherein the master member is a buffing plate providing a forward end part on which is carried a buffing jaw-forming member formed by a shaped member of generally U-shaped cross-section.
 3. A coupling according to claim 2 wherein in the region in which the buffing jaw member co-operates with said buffing plate, the U-shaped cross-section of the buffing jaw member has limb portions of unequal lengths, the longer thereof extending adjacent the forward vertical terminal edge of the buffing plate.
 4. A coupling according to claim 2 wherein the coupling arm is formed by the assembly of the buffing plate in a box structure with three plate members forming respectively an upper plate, a lower plate, and a side plate portion which extends parallel to at least a part of the buffing plate.
 5. A coupling according to claim 4 wherein an unlatching actuating means guide is supported on the lower plate.
 6. A coupling according to claim 4 wherein said box structure forms at the rearward end of the arm a tube part of substantially rectangular cross-section whose long edges extend horizontally, and said pivot member comprises a body portion carrying an axial extension forming an anchoring lug portion of a cross-section adapted to engage within said tube part.
 7. A coupling according to claim 6 wherein said anchoring lug portion is hollowed axially and is axially extended forwardly by a blind-end member which is disposed within said tube part, the hollow in the anchoring lug portion and the blind-end member forming a housing receiving a pivot spring having a forward end which abuts against the blind end of said member.
 8. A coupling according to claim 7 wherein the rearward end of each of said upper and lower plates is disposed rearwardly of said anchoring lug portion and is of a substantially semi-circular convex terminal profile, and wherein the pivot member body portion has on upper and lower surfaces shoulders of substantially semi-circular profile so arranged that the convex terminal profile of each of the upper and lower plates fits to the respective shoulder.
 9. A coupling according to claim 7 wherein adjacent the rearward end of the box structure there is provided a shaped reinforcing metal plate member which extends parallel to the upper and lower plates and is equidistant therefrom and whose rearward end abuts against and is fastened to the blind-end face of the blind-end member the plate member also being secured as a cross-bracing means to the buffing plate and the side plate portion.
 10. A coupling according to claim 4 wherein said upper and lower plates are enlarged forwardly into stiffening wing portions and wherein a pulling jaw-forming member is secured to said wing portions.
 11. A coupling according to claim 10 wherein an intermediate strengthening plate is disposed between said upper and lower plates parallel to the lower plate and is secured along one of its longitudinal edges to said side plate portion, its forward end portion being so shaped as also to be joined to said pulling jaw-forming member.
 12. A coupling according to claim 11 wherein an unlatching actuating means guide is secured between the lower and the intermediate plates.
 13. A coupling according to claim 10 whereIn the frontal plate has an upper part which is disposed as a cross-bracing means between the part of the buffing plate carrying the buffing jaw member and the rearward edge of the pulling jaw member.
 14. A coupling according to claim 13 wherein said side plate portion has a front edge which abuts against said upper part of the frontal plate, in the vicinity of the rearward edge of the pulling jaw member.
 15. A coupling according to claim 4 wherein said buffing plate has, in a forward direction, a shank plate portion parallel to the side plate portion, an intermediate plate portion which is turned outwardly through a given angle, and a front plate portion which is diverted inwardly through an angle greater than said given angle, so as to be at an acute angle to the shank plate portion.
 16. A coupling according to claim 15 wherein said intermediate and front plate portions project upwardly above said upper plate and a cap metal plate member is secured to the upwardly projecting parts rearwardly of the frontal plate, thereby to form a housing for latching mechanism.
 17. A coupling according to claim 3 wherein a plurality of stiffening plate members are fitted within the buffing jaw member, the shape of the plate members being substantially adapted to the cross-sectional shape of the buffing jaw member, except for angle corners of the cross-section of the buffing jaw member, at which corners openings are provided for liquid flow through the buffing jaw member.
 18. A coupling according to claim 1 and further including a male guide assembly arranged in vertical alignment with the buffing jaw.
 19. A coupling according to claim 18 wherein said male guide assembly comprises a forwardly extending horn member and an inclined guide surface member of metal plate extending rearwardly of the horn member, the horn member and the guide surface member being assembled around a lower portion of the buffing jaw member and a member which forms part of the adjacent said side wall of the passageway also being connected at its upper edge to said guide surface member.
 20. A coupling according to claim 19 wherein said lower portion of the buffing jaw member is of a cross-section comprising two limb portions at right angles to each other, one limb portion being secured to the horn member and the guide surface member and the other limb portion comprising, at the level at which the lower portion is secured to the horn member, a portion which is shaped in transverse section and which is increased in thickness for stiffening purposes.
 21. A coupling according to claim 19 wherein said inclined guide surface member is strengthened by a rib portion of triangular shape, one of its edges being secured to the inclined guide surface member, a second of its edges being secured to the horn member, and the third of its edges extending outwardly.
 22. A coupling according to claim 19 wherein the bottom member of the passageway is formed by a metal base plate member which extends below said horn member of the male guide assembly with which it is made peripherally integral.
 23. A coupling according to claim 1 wherein the one of said side walls that is at the pulling jaw side of the coupling includes a post member which in its lower part carries a horizontal bearing for a coupler fixing shaft, and three metal plate members, respectively an upper, a middle and a lower plate member, the plate members being joined at one of their side edges to the post member in a single vertical plane, thereby to form an apertured wall portion.
 24. A coupling according to claim 1 and further including a female guide assembly disposed in vertical alignment with the pulling jaw.
 25. A coupling according to claim 24 wherein said female guide assembly comprises a laterally projecting restraining horn member, a vertical deflector below the horn member, and a projecting portion forming a shoe below the deflector member, the horn member, deflector and shoe defining a guide passage for receiving a male guide assembly Of a co-acting coupling for assisting in coupling.
 26. A coupling according to claim 25 wherein said frontal plate has a substantially vertical solid base portion having a bottom end which is secured to an adjacent part of a member carrying said shoe, the base portion also being secured to said horn member, and over the whole of its adjacent vertical edge to the deflector.
 27. A coupling according to claim 26 wherein said shoe carrier member co-operates by way of its upper face with the deflector and a post member forming part of the passageway side wall at the pulling jaw side of the coupling.
 28. A coupling according to claim 26 wherein a member forming a lower bearing for an advance spindle is secured on the upper face of the shoe carrier member, rearwardly of said deflector and in vertical alignment with an upper bearing member which is associated with an unlatching actuating guide means.
 29. A coupling according to claim 26 wherein said shoe is formed by a shaped projecting extension on the upper face of the shoe carrier member.
 30. A coupling according to claim 26 wherein said bottom member is formed by a metal base plate member and the shoe-carrier member which is joined to the base plate member.
 31. An automatic central buffer coupling of the Willison type, comprising a coupling arm providing a forward end and a rearward end, a buffing jaw at the forward end of the coupling arm, a pulling jaw at the forward end of the coupling arm adjacent the buffing jaw, a first guide assembly adjacent the buffing jaw, a second guide assembly adjacent the pulling jaw, the guide assemblies of two said couplings to be coupled being co-operable for mutual relative positioning thereof, a pivot member at the rearward end of the arm, and a main stress-carrying member which extends in one continuous piece from the pivot member to the buffing jaw, the components thus forming the coupling being assembled together by welding around said main member as the basic component of the coupling.
 32. A coupling according to claim 31 wherein the arm is of a box structure and the main member is a buffing plate which forms a side of the box structure, the buffing jaw being formed by a buffing jaw member welded to the forward end of the buffer plate.
 33. A coupling according to claim 31 wherein a frontal plate is disposed between the buffing and pulling jaws and defines an aperture for a latching mechanism.
 34. A coupling according to claim 31 wherein the coupling arm includes two side wall members and a base member which define a passageway for conduit means for interconnecting two coupled rail vehicles.
 35. A coupling according to claim 31 wherein said first guide assembly comprises a forwardly projecting guide horn which is extended rearwardly by an inclined surface, and the second guide assembly forms a passage for receiving the guide horn of a co-acting coupling to be coupled, the passage being formed by a laterally projecting restraining horn, a vertical deflector surface member below the restraining horn, and a substantially laterally and forwardly projecting shoe disposed below the deflector surface member. 